Hull for small watercraft

ABSTRACT

A hull for a watercraft has a longitudinal axis generally extending from fore to aft of the watercraft. The hull includes a seat pedestal forming at least two side walls supporting a seat. The side walls generally extend longitudinally relative to the hull. The seat pedestal defines an engine compartment in which an engine is placed. Each side wall defines a maintenance opening communicating with the engine compartment. The openings are elongated along the longitudinal axis. Normally, caps close the respective openings. Each cap has a bulged out configuration to form an inner recessed area therein. A portion of an exhaust conduit extends beyond the opening to occupy one of the recessed areas. In one arrangement, an air induction system includes a plenum chamber unit that has a portion disposed close to the opening. The portion of the plenum chamber unit also defines another opening thereon.

PRIORITY INFORMATION

[0001] This application is based on Japanese Application No. 2001-038200, filed Feb. 15, 2001, the entire contents of which is hereby expressly incorporated by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates generally to a hull for a small watercraft, and more particularly to an improved hull for a small watercraft that includes a seat pedestal defining an internal space in which an engine can be positioned.

[0004] 2. Description of Related Art

[0005] Relatively small watercraft such as, for example, personal watercraft have become very popular in recent years. This type of watercraft is quite sporting in nature and carries one or more riders. An internal combustion engine powers a jet propulsion unit that propels the watercraft by discharging water rearwardly. The engine lies within an engine compartment in front of a tunnel which is formed in the rear and underside of the watercraft. The jet propulsion unit generally is placed within the tunnel and includes an impeller driven by the engine to discharge the water.

[0006] A hull of the watercraft typically includes a seat pedestal having side walls bridged by a seat. Footwells are positioned on either side of the side walls. The seat pedestal and the footwells together define a riders' area. The seat pedestal also defines an internal space, at least a portion of which is available for an engine compartment in which the engine is placed. The internal area and particularly the engine, can be accessed by removing a panel which covers an opening formed in the hull for maintenance of the engine, engine components or watercraft components enclosed in the internal space. However, due to the location and/or the size of the opening, access to some parts of the engine or components is extremely difficult if the part is located toward the bottom of the space or is disposed behind another part. For example, an oil filter unit of a lubricant system usually is positioned at the bottom of the engine. Replacement of such a filter therefore is one of the most difficult tasks associated with regular maintenance.

[0007] U.S. Pat. No. 5,743,206 discloses circular ports formed on the side walls of a seat pedestal. The ports are closed with a round cap. The ports and the caps have cooperating threads so that the caps can be sealed to the ports and thus prevent water invasion. Additionally, the ports are sized and positioned to allow a user to remove and replace the spark plugs from the engine, a task that is typically performed with one hand.

SUMMARY OF THE INVENTION

[0008] One aspect of the present invention includes the realization that there are other procedures which a mechanic could perform more easily if ports on the sides of seat pedestals were larger. Additionally, it has been found that it is more difficult to manufacture and operate large port holes that are round and threaded. For example, the larger a port is, the more difficult is it to align the threads on the corresponding cap. Additionally, to make a port, for example, approximately the same length as the engine, the port would be nearly as tall as the seat pedestal. Such a port could compromise the rigidity of the seat pedestal. Thus, it is desirable to provide an improved hull for a small watercraft that can allow a rider, mechanic or repairperson to work on part of an engine or other components within the hull with both hands and/or enhanced visibility of the components.

[0009] In accordance with an aspect of the present invention, a watercraft comprises a hull. The hull has a longitudinal axis generally extending from fore to aft of the watercraft. The hull includes a seat pedestal forming at least two side walls supporting a seat. The side walls generally extend along the longitudinal axis. At least one of the side walls defines an opening communicating with an internal space defined by the seat pedestal. The opening is elongated longitudinally relative to the hull.

[0010] In accordance with another aspect of the present invention, a watercraft includes a hull, an engine supported by the hull. The engine includes an engine body and an induction system configured to guide air to the engine body. An inlet of the induction system faces toward the engine body and a portion of the engine body extends below the inlet.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] These and other features, aspects and advantages of the present invention will now be described with reference to the drawings of preferred embodiments which are intended to illustrate and not to limit the invention. The drawings comprise seven figures.

[0012]FIG. 1 is a side elevational and sectional view of a personal watercraft configured in accordance with a preferred embodiment of the present invention.

[0013]FIG. 2 is a top plan view of the watercraft of FIG. 1. Certain internal components of the watercraft are schematically shown in solid line.

[0014]FIG. 3 is a partial sectional and rear view (taken along the line 3-3 of FIG. 1) the watercraft and an engine disposed within the hull, the hull including side walls having maintenance openings closed with closure members.

[0015]FIG. 4 is a front, top, and port side perspective view of the hull and the engine shown in FIG. 3. The hull is shown in phantom and the bow part of the hull is illustrated as being cut away.

[0016]FIG. 5 is a top plan view of a modification of the watercraft illustrated in FIG. 1. Similarly to FIG. 2, certain internal components of the watercraft are schematically shown in solid line.

[0017]FIG. 6 is a starboard side elevational and partial sectional view of the engine shown in FIG. 5. A maintenance opening on the starboard side is illustrated in phantom.

[0018]FIG. 7 is a partial sectional and rear view of the watercraft shown in FIG. 5.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

[0019] With reference to FIGS. 1-4, an overall construction of a personal watercraft 30 configured in accordance with the present invention is described below.

[0020] The personal watercraft 30 includes a hull 34 generally formed with a lower hull section 36 and an upper hull section or deck 38. Both the hull sections 36, 38 are made of, for example, a molded fiberglass reinforced resin or a sheet molding compound. The lower hull section 36 and the upper hull section 38 are coupled together to define an internal space 40 therebetween. An intersection of the hull sections 36, 38 is defined in part along an outer surface gunwale or bulwark 42. The hull 34 houses an internal combustion engine 44 that powers the watercraft 30.

[0021] As shown in FIGS. 2 and 3, the hull 34 defines a center plane CP that extends generally vertically from bow to stern with the watercraft 30 resting in normal upright position. The center plane CP includes a longitudinal axis LA of the watercraft 30. Along the center plane CP, the upper hull section 38 generally includes a hatch cover 48, a steering mast 50 and a seat 52 one after another from fore to aft.

[0022] In the illustrated embodiment, a bow portion of the upper hull section 38 slopes upwardly and an opening 54 is defined through which a rider R (FIG. 3) can conveniently access a storage area 56 formed within the internal space 40 with bulkheads 57. The hatch cover 48 is hinged to open and close the opening 54. The term “rider” in this description means a rider, user, mechanics or repairperson in the broad sense of the word unless indicated otherwise or otherwise readily apparent from the context use.

[0023] The steering mast 50 extends generally upwardly toward the top of the bow portion to support a handle bar 58. The handle bar 58 is provided primarily to allow the rider R to change a thrust direction of the watercraft 30. The handle bar 58 also carries control devices such as, for example, a throttle lever (not shown) for controlling the engine 44.

[0024] The seat 52 extends fore to aft along the center plane CP at a location behind the steering mast 50. The seat 52 is configured generally with a saddle shape so that the rider R can straddle the seat 52. The upper hull section 38 includes a seat pedestal 60 that forms a pair of side walls 62 which support at least a portion of the seat 52. The side walls 62 extend fore to aft along the longitudinal axis LA of the watercraft 30 and becomes wider toward the bottom.

[0025] The seat 52 comprises a cushion 64 and a rigid backing 66 and is detachably supported by the seat pedestal 60 with the backing 66 disposed atop the pedestal 60. In the illustrated embodiment, the seat 52 is formed of a forward portion and a rearward portion, each independently connected to the pedestal 60.

[0026] An access opening 68 is defined on the top surface of the pedestal 60 and under the seat 52. A rider, mechanic or repairperson can conveniently access the internal space 40 through the access opening 68. Footwells 70 are defined on either side of the side walls 62 and on an upper surface of the upper hull section 38. The illustrated footwells 70 are generally flat and slope upwardly toward the aft of the watercraft 30. The seat 52 and the footwells 70 together define a riders' area.

[0027] The upper hull section 38 also defines front and rear storage boxes 74, 76. The front storage box 74 is located between the steering mast 50 and the seat 52, while the rear storage box 76 is located in the rear of the seat 52. The storage box 74 preferably is closed by a cap 77 that is hingedly coupled with the box 74. When the cap 77 is detached, the storage box 74 is available for containing a beverage container, gloves, riding equipment, and the like.

[0028] The entire internal space 40 of the illustrated arrangement is available for an engine compartment. Thus, the reference numeral 40 can also indicate the engine compartment in this description. One or more bulkheads can divide the internal space 40 into multiple compartments, at least one being the engine compartment. In the illustrated embodiment, one bulkhead 78 is disposed between the engine 44 and a rear portion of the hull 30.

[0029] A fuel tank 82 is placed in the engine compartment 40 under the bow portion of the upper hull section 38. The fuel tank 82 is coupled with a fuel inlet port (not shown) positioned atop the upper hull section 38 through a proper duct.

[0030] A pair of air ducts or ventilation ducts (not shown) is provided on either side of the upper hull section 38 so that the ambient air can enter and exit the engine compartment 40 through the ducts. Except for the air ducts, the internal space 40 is substantially sealed to protect the engine 44, a fuel supply system including the fuel tank 82 and other systems or components from water.

[0031] The engine 44 preferably is placed within the engine compartment 40 generally under the seat 52, although other locations are also possible (e.g., beneath the steering mast 50 or in the bow). The rider R can access the engine 44 through the access opening 68 by detaching the seat cushion 60 from the seat pedestal 60.

[0032] The engine 44 operates on a four-cycle combustion principle. The engine 44 comprises a cylinder block 90 that preferably defines four cylinder bores 92 spaced apart from each other from fore to aft along the center plane CP. That is, four cylinders Cy. 1, Cy. 2, Cy. 3 and Cy. 4 preferably are aligned as shown in FIG. 2. The engine 44 thus is a L4 (in-line four cylinder) type. The illustrated four-cycle engine, however, merely exemplifies one type of engine. Engines having other number of cylinders including a single cylinder, and having other cylinder arrangements (V and W type) and other cylinder orientations (e.g., upright cylinder banks) are all practicable.

[0033] With reference to FIG. 3, each cylinder bore 92 has a center axis CA that is slanted from the center plane CP with an angle θ so that the overall height of the engine 44 is shorter. All the center axes CA of the cylinder bores 92 preferably are inclined relative to the center plane CP at the same angle.

[0034] Pistons 94 are reciprocally disposed within the cylinder bores 92. A cylinder head member 96 is affixed to an upper end portion of the cylinder block 90 to close respective upper ends of the cylinder bores 92, and thus defines combustion chambers with the cylinder bores 92 and the pistons 94.

[0035] A crankcase member 100 is affixed to a lower end portion of the cylinder block 90 to close respective lower ends of the cylinder bores 92 and to define a crankcase chamber 102 with the cylinder block 90. A crankshaft 104 is journaled for rotation by the crankcase member 100. Connecting rods 106 couple the crankshaft 104 with the pistons 94 so that the crankshaft 104 rotates with the reciprocal movement of the pistons 94.

[0036] The cylinder block 90, the cylinder head member 96 and the crankcase member 100 together define an engine body 108. The engine body 108 preferably is made of aluminum based alloy. In the illustrated arrangement, the engine body 108 is oriented in the engine compartment 40 to position the crankshaft 104 generally parallel to the center plane CP and to extend generally along the longitudinal axis LA. In the illustrated embodiment, a center axis 105 of the crankshaft 104 is offset from the center plane CP a distance L as shown in FIG. 3. In some arrangements, other orientations of the engine body 108 also are possible (e.g., with a transverse or vertical oriented crankshaft).

[0037] Engine mounts 112 extend from either side of the engine body 108. The engine mounts 112 preferably include resilient portions made of flexible material, for example, a rubber material. The engine body 108 is mounted on the lower hull section 36, specifically, a hull liner, by the engine mounts 112 so that vibrations from the engine 44 are attenuated.

[0038] The engine 44 preferably comprises an air induction system to guide air to the combustion chambers. The illustrated air induction system includes four inner intake passages 114 defined in the cylinder head member 96. The intake passages 114 communicate with the associated combustion chambers through one or more intake ports 116. Intake valves 118 are provided at the intake ports 116 to selectively connect and disconnect the intake passages 114 with the combustion chambers. In other words, the intake valves 118 move between open and closed positions of the intake ports 116.

[0039] Preferably, the air induction system also includes a plenum chamber unit or air intake box 122 disposed above the engine body 108 and below the seat 52. The illustrated plenum chamber unit 122 has a generally rectangular shape in a plan view (FIG. 2) and defines a plenum chamber therein for smoothing intake air and quieting intake air. Other shapes of the plenum chamber unit 122 of course are possible, but it is preferable to make the plenum chamber as large as possible within the space provided between the engine body 108 and the seat 52.

[0040] With continued reference to FIG. 3, the plenum chamber unit 122 preferably comprises an upper member and a lower member coupled together. The lower member defines four apertures disposed in line and generally parallel to the center plane CP.

[0041] Preferably, four throttle bodies 126 extend through the apertures and are fixed to the lower chamber member. Each throttle body 126 has an inlet 128 that opens to the interior of the plenum chamber. The throttle bodies 126 are generally positioned on the port side of the plenum chamber. Respective bottom ends of the throttle bodies 126 are coupled with the associated inner intake passages 114. The throttle bodies 126 preferably extend generally vertically but slant toward the port side oppositely from the center axis CA of the engine body 108. Air in the plenum chamber thus is drawn to the combustion chambers through the throttle bodies 126.

[0042] A throttle valve 130 is journaled for pivotal movement on each throttle body 126 with a valve shaft. Preferably, the valve shaft links all of the throttle valves 130. The pivotal movement of the valve shaft is controlled by the throttle lever on the handle bar 58 through a control cable. The rider R thus can control an opening degree of the throttle valves 130 by operating the throttle lever to obtain various engine speeds. That is, an amount of air passing through the throttle bodies 126 is measured or regulated by this mechanism. Normally, the greater the opening degree, the higher the rate of airflow and the higher the engine speed.

[0043] One or more air inlet ports 134 are formed on the lower member to draw air into the plenum chamber. In the illustrated embodiment, a filter assembly or air cleaner unit 136 is positioned on the starboard side of the plenum chamber and opposite the throttle bodies 126. The filter assembly 136 contains at least one filter element therein.

[0044] The engine 44 preferably comprises an indirect or port injected fuel supply system. The fuel supply system includes four fuel injectors 138 with one injector allotted to each throttle body 126. The fuel injectors 138 are affixed to a fuel rail (not shown) that is mounted on the throttle bodies 126. The fuel injectors 138 have injection nozzles opening downstream of the throttle valves 130. The fuel injectors 138 spray fuel through the nozzles at certain injection timing and for certain duration under control of an electronic control unit (ECU) (not shown). The sprayed fuel is drawn into the combustion chambers together with the air to form an air/fuel charge therein. A direct fuel injection system that sprays fuel directly into the combustion chambers can replace the indirect fuel injection system described above. Moreover, other charge forming devices such as, for example, carburetors can be used instead of the fuel injection system.

[0045] The engine 44 preferably comprises a firing or ignition system. The ignition system includes four spark plugs (not shown), one spark plug allotted to each combustion chamber. The spark plugs are affixed to the cylinder head member 96 so that electrodes, which are defined at ends of the plugs, are exposed to the respective combustion chambers. The spark plugs fire the air/fuel charges in the combustion chambers at an ignition timing under control of the ECU. The air/fuel charge thus is burned within the combustion chambers to move the pistons 92 generally downwardly.

[0046] The engine 44 also includes an exhaust system configured to guide burnt charges, i.e., exhaust gases, from the combustion chambers. In the illustrated embodiment, the exhaust system includes four inner exhaust passages 142 defined within the cylinder head member 96. The exhaust passages 142 communicate with the associated combustion chambers through one or more exhaust ports 144. Exhaust valves 146 are provided at the exhaust ports 144 to selectively connect and disconnect the exhaust passages 142 from the combustion chambers. In other words, the exhaust valves 146 move between open and closed positions of the exhaust ports 144.

[0047] In the illustrated embodiment, an exhaust manifold 150 depends from the cylinder head member 96 at a starboard side surface thereof as shown in FIG. 3. The exhaust manifold 150 is connected with the inner exhaust passages 142 to collect exhaust gases from the respective inner exhaust passages 142. An exhaust conduit 152 is connected with the exhaust manifold 150 downstream thereof and extends forwardly on the starboard side, turns toward the port side and then further extends rearwardly on the port side. The exhaust conduit 152 is one of engine component which extends along the engine body 108. The exhaust conduit 152 can comprise two or more conduit sections. An end portion of the exhaust conduit 152 in the illustrated arrangement passes through the bulkhead 78 to the rear portion of the hull 34. The reference numeral 152S generally indicates part of the exhaust conduit 152 extending on the starboard side, while the reference numeral 152P generally indicates other part of the exhaust conduit 152 extending on the port side. The illustrated exhaust manifold 150 and the exhaust conduit 152 at least in part include a water jacket 154 coaxially surrounding exhaust passages 155 as shown in FIG. 3.

[0048] The end portion of the exhaust conduit 152, which is the furthest downstream portion of the conduit part 152P, is connected to a water-lock or first exhaust silencer 156 disposed in the rear portion of the hull 34 on the port side. The water-lock 156 is connected to a second exhaust silencer 158 through a connecting pipe 160. The second exhaust silencer 158 is disposed on the center plane CP and is positioned higher than the water-lock 156. A discharge pipe 162 extends generally rearwardly from the second exhaust silencer 158 and is connected to a portion of a tunnel 164 on the starboard side.

[0049] The tunnel 164 is a recessed portion formed on the underside of the lower hull section 36. The discharge pipe 162 opens to the exterior of the watercraft 30 in a submerged position. Thus, the exhaust gases are discharged to a body of water surrounding the watercraft 30 through the discharge pipe 162. The respective exhaust silencers 156, 158 define one or more expansion chambers therein to reduce exhaust noise. In addition, because of the particular arrangement of the last part of the exhaust system, the water that can enter the opening part of the discharge pipe 162 is inhibited from going further to the exhaust conduit 152 not only when the watercraft 30 is in the normal position but also in any capsized positions as is well known.

[0050] The engine 44 includes a valvetrain drive for actuating the intake and exhaust valves 118, 146. In the illustrated embodiment, the valvetrain drive comprises a double overhead camshaft drive including an intake camshaft 168 and an exhaust camshaft 170. The intake and exhaust camshafts 168, 170 actuate the intake and exhaust valves 118, 146, respectively. The intake camshaft 168 extends generally horizontally over the intake valves 118 from fore to aft in parallel to the center plane CP, while the exhaust camshaft 146 extends generally horizontally over the exhaust valves 146 from fore to aft also in parallel to the center plane CP. Both the intake and exhaust camshafts 168, 170 are journaled for rotation by the cylinder head member 96 with a plurality of camshaft caps. The camshaft caps holding the camshafts 168, 170 are affixed to the cylinder head member 96. A cylinder head cover member 172 extends over the camshafts 168, 170 and the camshaft caps, and is affixed to the cylinder head member 96 to define a camshaft chamber.

[0051] The intake and exhaust camshafts 168, 170 each have cam lobes. Each cam lobe is associated with each one of the intake valves 118 and the exhaust valves 146, respectively. The intake and exhaust valves 118, 146 are biased to a closed position via, for example, springs. When the intake and exhaust camshafts 168, 170 rotate, the respective cam lobes push the associated valves 118, 146 to open the respective ports against the biasing force of the springs. The air thus can enter the combustion chambers when the intake valves 118 are opened and the exhaust gases can move out from the combustion chambers when the exhaust valves 146 are open.

[0052] The crankshaft 104 preferably drives the intake and exhaust camshafts 168, 170. Preferably, the respective camshafts 168, 170 have driven sprockets affixed to ends thereof. The crankshaft 104 also has a drive sprocket. Each driven sprocket has a diameter which is twice as large as a diameter of the drive sprocket. A flexible transmitter such as, for example, a timing chain or belt is wound around the drive and driven sprockets. When the crankshaft 104 rotates, the drive sprocket drives the driven sprockets via the timing chain, and then the intake and exhaust camshafts 168, 170 rotate also. The rotational speed of the camshafts 168, 170 are reduced to half of the rotational speed of the crankshaft 104 because of the differences in diameters of the drive and driven sprockets. A tensioner of the flexible transmitter is provided to give proper tension to the flexible transmitter. A tension adjuster 178 (FIG. 3) is provided to adjust the tension of the tensioner. The tension adjuster 178 exposes itself at a side surface of the cylinder head member 96 on the starboard side.

[0053] Ambient air enters the engine compartment 40 through the air ducts. The air is introduced into the plenum chamber defined by the plenum chamber unit 122 through the air inlet ports 134 and then drawn into the throttle bodies 126. The filter assembly 136 removes foreign particles from the air. The air in the plenum chamber is supplied to the combustion chambers.

[0054] The throttle valves 130 in the throttle bodies 126 regulate an amount of the air flowing toward the combustion chambers. The air flows into the combustion chambers when the intake valves 118 are opened. At the same time, the fuel injectors 138 spray fuel into the intake ports 116 under the control of the ECU. Air/fuel charges are thus formed and are delivered to the combustion chambers.

[0055] The air/fuel charges are fired by the spark plugs also under the control of the ECU. The burnt charges, i.e., exhaust gases, are discharged to the body of water surrounding the watercraft 30 through the exhaust system. The combustion of the air/fuel charges causes the pistons 94 reciprocate within the cylinder bores 92 and thereby causes the crankshaft 104 to rotate.

[0056] The engine 44 preferably includes a lubrication system that delivers a lubricant, such as oil, to engine portions for inhibiting frictional wear of such portions. In the illustrated embodiment, a closed-loop type, dry-sump lubrication system is employed. Lubricant oil for the lubrication system preferably is stored in a lubricant reservoir or tank 182 disposed at the rear of the engine body 108 and is affixed thereto.

[0057] An oil filter unit 184 is detachably mounted on the crankcase member 100 on the port side of the engine body 108. The oil filter unit 184 contains at least one filter element to remove foreign substances from the lubricant oil circulating in the lubrication system. The oil filter unit 184 also can separate water component from the lubricant oil. The lubrication system includes one or more oil pumps that are preferably driven by the crankshaft 104 in the circulation loop to deliver the lubricant oil from the lubricant reservoir 182 to the engine portions that need lubrication and then return it to the reservoir 182.

[0058] The watercraft 30 preferably employs a water cooling system for cooling the engine body 108 and the exhaust system. Preferably, the cooling system is an open-loop type that introduces cooling water from the body of water in which the watercraft is operating. The cooling system can include a water pump and a plurality of water jackets and/or conduits. The foregoing water jacket 154 (FIG. 3) is part of the water jackets.

[0059] The engine 44 and the particular external portions of the exhaust system is disclosed in, for example, a co-pending U.S. application filed Jan. 31, 2001, titled INTERNAL COMBUSTION ENGINE, which is Ser. No. 09/918,980, the entire contents of which is hereby expressly incorporated by reference.

[0060] In the illustrated embodiment, a jet pump assembly 188 propels the watercraft 30. The jet pump assembly 188 is mounted in the tunnel 164. The tunnel 164 has a downward facing inlet port 190 opening toward the body of water. A pump housing 192 of the pump assembly 188 is disposed within a portion of the tunnel 164 and communicates with the inlet port 190. An impeller 194 is journaled for rotation within the pump housing 192.

[0061] An impeller shaft 196 extends forwardly from the impeller 194 and is coupled with an output shaft 198 via a coupling unit 200. The output shaft 198 is connected with the crankshaft 104 of the engine 32 to output the engine power. An axis 202 (FIG. 3) of the output shaft 198 (FIG. 3) extends on the center plane CP. Because the axis 105 of the crankshaft 104 is offset from the center plane CP in the illustrated arrangement as shown in FIG. 3, a connecting mechanism couples the crankshaft 104 with the output shaft 198. In the illustrated arrangement, a gear connection (not shown) is employed for the mechanism. The crankshaft 104 drives the impeller shaft 196 through the gear connection, the output shaft 198 and the coupling unit 200 accordingly.

[0062] A rear end of the pump housing 192 defines a discharge nozzle 206. A deflector or steering nozzle 208 is affixed to the discharge nozzle 206 for pivotal movement about a steering axis which extends approximately vertically. A cable connects the deflector 208 with the steering mast 50 so that the rider R can steer the deflector 208, and thereby change the direction of travel of the watercraft 30. Additionally, a reverse bucket 210 is pivotally mounted on the deflector 208 about an axis which extends generally horizontally. The rider R thus can move the watercraft 30 backwardly by lowering the reverse bucket 210 over the nozzles 206, 208. The reverse bucket 210 is configured such that when it is in a lowered position (not shown), water discharged through the steering nozzle 208 is directed forwardly, thus causing rearward movement of the watercraft 30.

[0063] When the crankshaft 104 of the engine 32 drives the impeller shaft 196 through the output shaft 198, the impeller 194 rotates. Water is drawn from the surrounding body of water through the inlet port 190. The pressure generated in the pump housing 174 by the impeller 194 produces jet stream of the water that is discharged through the discharge nozzle 206 and the deflector 208. The water jet produces thrust to propel the watercraft 30. The rider R can steer the deflector 208 with the handle bar 58 of the steering mast 50 to turn the watercraft 30 in either right or left direction. In the illustrated arrangement, the jet pump assembly 188 also functions as the water pump of the cooling system with a portion of the water pressurized by the impeller 194 being drawn off for the cooling system, as known in the art.

[0064] The access opening 68 provided under the seat 52 conveniently is used for maintenance of the engine 44, engine related components and/or watercraft related components. However, certain components are not easily accessed from the opening 68 because they are positioned distally from the opening 68. Some components are located behind other components and thus, maintenance or repair procedures can be difficult.

[0065] For example, the oil filter unit 184 is deep within the engine compartment and beneath a portion of the exhaust system. The tension adjuster 178 is placed behind the plenum chamber unit 122.

[0066] In accordance with another aspect of the present invention, the watercraft 30 thus has additional maintenance openings. With reference to FIGS. 2-4, the additional maintenance openings and arrangements around the openings are described in detail below.

[0067] In the illustrated arrangement, the side wall 62 of the seat pedestal 60 on the starboard side defines a maintenance opening 220S communicating with the engine compartment 40, while the side wall 62 of the seat pedestal 60 on the port side defines another maintenance opening 220P also communicating with the engine compartment 40. The respective openings 220S, 220P are oblong and elongated fore to aft generally parallel to the longitudinal axis LA.

[0068] The openings 220S, 220P preferably are positioned in proximity to engine portions, engine related components and/or watercraft related components. The oil filter unit 184, the tension adjuster 178, the spark plugs and the engine mounts 112 are exemplary engine portions. The engine related components include, for example but without limitation, the external portions of the exhaust system and the fuel tank 82. The watercraft related components in turn include, for example but without limitation, the air ducts and a bilge pump, if any, to bail out water at the bottom of the internal space 44. Preferably, the openings 220S, 220P are positioned at vertical locations with appropriate distances from top and bottom ends of the walls 62.

[0069] The openings 220S, 220P can have a length that is approximately the same length as the engine body 108. This provides an additional advantage by allowing a rider or mechanic to access various components with relative ease. For example, certain components, such as the exhaust manifold 150, are mounted with numerous mounting bolts disposed along the length of the engine body. Thus, by sizing the openings 220S, 220P with a length that is approximately as long as the engine body 108, a rider or mechanic can see and access such an arrangement of bolts more easily than through those access openings of the prior art.

[0070] Both the horizontal and vertical positions of the openings 220S, 220P can be determined at locations that are mostly close to major and/or primary maintenance portions and/or components. Also, the horizontal and vertical lengths of the openings 220S, 220P can be determined such that preferably both hands H are accessible to the maintenance portions.

[0071] For example, in the illustrated arrangement, the opening 220S on the starboard side is located forwardly than the opening 220P on the port side, and the vertical length of the opening 220P is longer than the vertical length of the opening 220S. Each horizontal length of the openings 220S, 220P is generally equal to each other, and the length is at least longer than a half of the access opening 68, preferably approximately as long as the engine body 108, as noted above.

[0072] The oil filter unit 184 can be located either in front of the engine body 108 or in the rear of the engine body 108. The openings 220S, 220P thus can be elongated sufficiently enough for at least one hand H of the rider R can reach the oil filter unit wherever it is located. The wider the openings 220S, 220P, the easier the hand or hands H reach target portions. The elongated openings 220S, 220P also are helpful for a rider or mechanic in seeing certain small components that could be inadvertently missed. That is, the elongated openings 220S, 220P also enhance visibility of the target portions.

[0073] Although any oblong configurations can be selected for the openings 220S, 220P, an oval shape, particularly, a streamline shape being enlarged at the forward end is one presently preferred shape. The openings 220S, 220P could be rectangular shape.

[0074] Caps or closure members 224S, 224P close the openings 220S, 220P, respectively. The respective caps 224S, 224P define a flange 226 on each peripheral edge thereof and are affixed to the side walls 62 by fasteners 228 such as, for example, bolts and nuts. A seal member 230 that has a shape corresponding to the shape of the flange 226 preferably is disposed between the flanges 226 and the peripheral edge of the openings 220S, 220P.

[0075] The caps 224S, 224P preferably has the same shape as of the openings 220S, 220P. Each illustrated cap 224S, 224P is bulged out to form an inner recessed area 232. The bulged configuration preferably is part of a stream line shape or tear drop shape so that possible noise made by wind is effectively reduced. Each recessed area 232 of the cap 224S, 224P preferably has a depth D between a top end and a bottom end as shown in FIG. 3. The depth D and the configuration of each cap 224S, 224P can be determined not to interfere with the legs LG and the ankles AK of the rider R.

[0076] The recessed areas 232 advantageously expand the internal space 40. Because of this expansion of the space 40, for example, a portion of the exhaust conduit 152P can extend beyond the opening 220P outwardly to occupy the increased space of the recessed area 232 of the cap 224P as shown in FIG. 3 and also shown in phantom line 228 of FIG. 2. The portion of the exhaust conduit 152P thus can be larger than that of a conventional construction without making the seat pedestal 60 itself wider. Thus, the output of the engine 44 can be improved without changing the basic shape of the pedestal 60 and seat 52.

[0077] Additionally, the illustrated portion of the exhaust conduit 152P is spaced apart from an inner surface of the cap 224P with a distance T. Thus, vibration of the conduit portion 152P caused by the engine operation, if any, is unlikely to be transferred to the seat pedestal 60. Alternatively, a portion of the plenum chamber of the air induction system can be positioned in the increased space of the recessed areas 232.

[0078] The recessed area 232 also can define a relatively large water pool where water can accumulate in the event that the watercraft 30 turns over. The larger water pool can reduce a chance that the water enter engine portions, the external portions of the exhaust system and/or the air induction system because a water level within the engine compartment 40 is inevitably lowered by the recessed areas 232.

[0079] In addition, because the illustrated recessed areas 232 are formed with the caps 224S, 224P that are separated from the seat pedestal 60 the upper hull section 38 including the seat pedestal 60 itself can be easily produced because no split dies are necessary in the molding process of the upper hull section 38.

[0080] It should be noted that the caps can take any shapes other than the illustrated bulged-shape. For example, a flat shape is applicable. Moreover, a shape dented toward inside of the internal space is also practicable.

[0081] With reference to FIGS. 5-7, a modification of the watercraft 30 is described below and is referred to generally with the reference numeral 30′. The same members, components, mechanisms and systems as those that have been already described will be assigned with the same reference numerals and will not be described repeatedly.

[0082] As shown in FIGS. 5-7, the watercraft 30′ has an exhaust system arranged differently from the exhaust system of the watercraft 30 described above with reference to FIGS. 1-4. In the watercraft 30′, an exhaust conduit 240 of the exhaust system is connected with the exhaust manifold 150 disposed on the starboard side and extends rearward straightly without turning around the engine body 108. The exhaust conduit 240 is coupled with the water-lock 156 which disposed on the starboard side. The water-lock 156, the second exhaust silencer 156, the connecting pipe 160 and the discharge pipe 162 in this arrangement are disposed in reversed positions relative to those in the watercraft 30′.

[0083] The discharge pipe 162 is connected to the tunnel 164 at a location on the port side accordingly. As shown in FIG. 6, the exhaust conduit 240 forms separate exhaust passages 242 therein to a location existing in the conduit 240 with the distance P from the exhaust manifold 150 and then forms a single exhaust passage 244 that unifies the separate passages 242. A water jacket 246 surrounds the exhaust passages 242, 244. The exhaust conduit 152 in the first arrangement generally has the same internal construction.

[0084] With reference to FIG. 7, a portion of the exhaust conduit 240 extends beyond the maintenance opening 220S outwardly and extends through the recessed area 232 of the cap 224S. This portion of the exhaust conduit 240 is spaced apart from an inner surface of the cap 224S with a distance T2. The oil filter unit 184 in this arrangement is disposed generally under the exhaust conduit 240 on the starboard side.

[0085] As shown in FIG. 7, the watercraft 30′ has an air induction system including a plenum chamber unit 250. The plenum chamber unit 250 is shaped generally as the letter L to extend downwardly on the port side of the engine 44.

[0086] The filter assembly 136 is positioned in the lower portion of the unit 250. The air inlet port 134 also is positioned at the lower portion and is surrounded by the filter assembly 136. The inlet port 134 opens towards the side surface of the cylinder block 90 of the engine 44.

[0087] The plenum chamber unit 250 defines an opening 252 in proximity to the maintenance opening 220P on the port side. The opening 252 can be elongated similarly to the opening 220P. The opening 252 preferably is closed by a flat cover member 254. The cover member 254 can be affixed to the plenum chamber unit 250 by fasteners 256 such as, for example, bolts and nuts.

[0088] Constructed as such, a rider can access the internal space 40 by detaching the cap 224P. Furthermore, with the cover member 254 removed, the rider can reach the filter assembly 136 in the plenum chamber unit 250 without dissembling the plenum chamber unit 250. The cap 224P preferably is spaced apart from the cover member 254 with a distance T3 so that any vibration of the plenum chamber unit 250 caused by the engine operation, if any, is not likely to be transferred to the seat pedestal 60.

[0089] As shown in FIG. 7, the relatively large crankcase member 100 extends under the inlet port 134. This is advantageous because the inlet port 134 is protected from bilge water that splashes in the engine compartment 40 during operation of the watercraft 30′. In addition, this arrangement of the inlet port 134 is particularly beneficial when the watercraft 30 capsizes because the crankcase member 100 will then extend over the inlet port 134, thereby protecting it from water falling toward the access opening 68. Further, because the inlet port 134 opens toward the center plane CP, the port 134 is not facing upward when the watercraft is upright or capsized which aids in preventing water from entering the inlet port 134.

[0090] Of course, the foregoing description is that of preferred constructions having certain features, aspects and advantages in accordance with the present invention. For instance, one of the side walls can have no maintenance opening. In other words, the watercraft can have only one opening on either one of the side walls. To the contrary, two or more openings can be provided on one side wall. One or more look-in windows, which are elongated and usually closed, can be provided separately from the maintenance openings. Accordingly, various changes and modifications may be made to the above-described arrangements without departing from the spirit and scope of the invention, as defined by the appended claims. 

What is claimed is:
 1. A watercraft comprising a hull having a longitudinal axis generally extending from fore to aft of the watercraft, the hull including a seat pedestal having first and second side walls supporting a seat, the side walls generally extending along the longitudinal axis, the first side wall defining a first opening communicating with an internal space defined by the seat pedestal, the opening being elongated longitudinally.
 2. The watercraft as set forth in claim 1 additionally comprising a closure member to close the first opening, and the closure member bulging outwardly from the first side wall of the seat pedestal.
 3. The watercraft as set forth in claim 1 additionally comprising an internal combustion engine placed within the internal space, the engine including an engine body and at least one engine component extending along the engine body.
 4. The watercraft as set forth in claim 3, wherein at least a portion of the engine component exists beyond the first opening.
 5. The watercraft as set forth in claim 4 further comprising a closure member to close the opening, the closure member bulging out to accommodate the portion of the engine component.
 6. The watercraft as set forth in claim 1 additionally comprising a multi-cylinder engine placed within the internal space, the engine including an engine body defining at least two cylinders aligned longitudinally relative to the hull, the first opening having a length that is approximately the same as a length of the engine body.
 7. The watercraft as set forth in claim 6, wherein the engine additionally includes at least one engine component connected with the respective cylinders, the engine component at least in part extending close to the first opening.
 8. The watercraft as set forth in claim 6, wherein the engine additionally includes at least one engine component connected with the respective cylinders, the engine component at least in part, is disposed beyond the first opening.
 9. The watercraft as set forth in claim 1 additionally comprising a second opening in the second side wall, the first and second openings being elongated with a length generally equal to each other.
 10. The watercraft as set forth in claim 9, wherein the first opening is positioned more forward than the second opening.
 11. The watercraft as set forth in claim 1 additionally comprising a second opening in the second side wall, a front end of the first opening being positioned more forward than a front end of the second opening.
 12. The watercraft as set forth in claim 1 additionally comprising a second opening in the second side wall, a rear end of the first opening being positioned more rearward than a rear end of the second opening.
 13. The watercraft as set forth in claim 1 additionally comprising a top wall bridging the side walls, the top wall defining a second opening, a longitudinal length of the first opening being longer than half a longitudinal length of the second opening.
 14. The watercraft as set forth in claim 1, wherein the hull additionally includes footwells positioned on either side of the seat pedestal.
 15. A watercraft comprising a hull, a seat pedestal supporting a seat, an engine compartment defined by the seat pedestal, an internal combustion engine disposed in the engine compartment, the engine including an engine body and at least one engine component extending along the engine body, the seat pedestal including at least first and second side walls extending longitudinally relative to the hull, at least the first side wall defining an oblong opening extending along the engine body.
 16. The watercraft as set forth in claim 15 additionally comprising a closure member configured to close the opening, the closure member bulging outwardly to accommodate the portion of the engine component.
 17. The watercraft as set forth in claim 16, wherein the engine component includes an exhaust conduit.
 18. The watercraft as set forth in claim 15, wherein the engine includes an air induction system and an exhaust system, and either one of the air induction system or the exhaust system at least in part exists close to the opening.
 19. The watercraft as set forth in claim 18 further comprising a closure member configured to close the opening, the closure member bulging out to form an inner recessed area, and at least one of a portion of the air induction system and a portion of the exhaust system being disposed in the recessed area.
 20. The watercraft as set forth in claim 18, wherein the air induction system includes a plenum chamber unit, a portion of the plenum chamber unit exists close to the opening.
 21. The watercraft as set forth in claim 20, wherein the plenum chamber unit defines a second opening facing to the first opening.
 22. The watercraft as set forth in claim 21, wherein the plenum chamber unit includes a filter element in proximity to the second opening.
 23. The watercraft as set forth in claim 15, wherein the hull additionally includes footrests positioned on either side of the side walls.
 24. A watercraft comprising a hull, an engine supported by the hull, the engine including an engine body, and an induction system configured to guide air to the engine body, an inlet of the induction system facing toward the engine body, and a portion of the engine body extending below the inlet.
 25. The watercraft according to claim 24, wherein a portion of the induction system extends over the inlet.
 26. The watercraft according to claim 24, wherein the engine body includes a cylinder block which is inclined toward a first side of the engine body, the inlet facing toward the second side of the engine body. 